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Just got my flat top CMMG upper today and my Magpul MBUS, I'll be taking it to the range soon and now I have a question. This is my first rifle I've ever owned, do I need to sight it in or does it shoot straight right out of the box with the MBUS? I've searched the board and done a quick google search and haven't found anything helpful.

Pic

Any responses are appreciated, thank you

You have to sight it in yourself so go out and burn ammo. Let us know how it shoots. Enjoy the new toy.

Yes, you need to sight it in. Those sights may be roughly centered, but that's a maybe.
Ideally you should boresight it at home. Buy one of those laser boresight tools and get it close enough to get on paper with the first round.
You install the laser in the muzzle and turn it on, pointed to the back fence or something 50 yds away. Then adjust the sights to the dot.
Saves lots of time and money.

Also, don't try to shoot from a rest with that cool 30-rnd mag.
A 20-round mag is much easier to handle because it doesn't stick down a foot.

You didn't say what you were going to do with the AR so I presume you'll be using it for self-defense and or plinking. The above suggestions are good. If you can't or don't use a bore sighter set up a target 25 yards away using a paper plate or sheet of typing paper aim for the middle (a spot on the plate or paper will help) Fire three rounds, determine what direction and how much you need to move the sights. Make your correction, fire three more rounds verify point of impact and decide if you need to make further corrections. Once you get the gun shooting to your mark at 25 yards, move the target to 50 yards and repeat the process if you are shooting 55 gr ammo and you have the rifle zeroed to hit point of aim a 50yards/merers you will be sighted to hit point of aim at 200 yards/meters. With the rifle sighted this way you can hold the center of an 8 " circle from 0 to about 275 yards/meters and be assured of a hit inside the circle.

Thanks for the responses. Yes I do plan on getting a 20 rd mag, just preparing for a ban

Here's a good link with some good info (not all will apply, because with a BUIS you don't have the ability to adjust for elevation with your rear sight):

http://ar15zeroing.com/" onclick="window.open(this.href);return false;

Another trick, if you don't want to buy a laser boresighter, separate your upper from lower and remove your bolt carrier group so that you can look directly down the barrel from back of the upper. Lightly clamp the upper somehow (vice covered with soft cloth onto the foregrip works well) and look through the barrel until you line up on an object at approximately your shooting distance. Clamp the vice tight enough so the upper won't move. Then adjust your sights until they also are lined up with whatever object you lined up with your barrel. NOTE: This is an old trick with bolt-action rifles that someone taught me, but works well with ARs too if you remove the upper from the lower. This trick actually works BETTER for me than a laser boresighter or one of those physical boresighter instruments. I've been on paper first shot every time with this trick.

(NOTE: edited post to remove attached target because wasn't printing correctly through web browser).

Remember that your upper receiver is a thin aluminum forging and without internal support, be very careful tightening in a vise.

Bob

Or, you could do what I did, if you don't have a boresighting laser. Just get out your laser pointer and go to town!
http://www.texaschlforum.com/viewtopic.php?f=87&t=31390" onclick="window.open(this.href);return false;

Just took it to the range for the first time this morning, made some minor adjustments at 25 and 50 yards and it shoots pretty straight. My grouping wasn't bad for the first time out but I've got a long way to go. Thanks for the help.